Production of lubricating oil dyes



Patented May 31, 1938 UNITED STATES PRODUCTION F LUBRIUATING on. DYES EjnarW. Carlson, Roselle, N." J., assignor to Standard Oil Development Company, a corporation of Delaware I No Drawing. Application August 22,1933,

Serial N0. 686,266

6 Claims.

This invention relates to a process of producing oils suitable for lubricating oil dyes. Specifically, it deals with the preparation of colored oil-soluble products by heat treatment of lowboiling cracked hydrocarbons.

It is desirable to impart to lubricating oils a rich green fluorescence giving a red color when viewed by transmitted light. This is especially so in the case of lubricating oils which do not have the desired color though meeting all the other requirements of good lubricating oils, such as gravity, viscosity, flash, pour, etc. To accomplish this the following procedure is followed, according to the present invention.

Relatively high boiling point petroleum oils, such as gas oils, are heated under pressure to partially decompose and form lighter oils such as gasoline. The gasoline fractions formed are separated from the other resulting products and subjected to further fractionation. First, an overhead distillate is separated, which is composed of gases such as methane, ethane, etc. and liquids such as propane, butane, pentane, hexane and unsaturated hydrocarbons. The liquid fraction is separated from the gases and further fractionated to produce two fractions, one composed mainly of propane and the other of the higher boiling hydrocarbons such as butane, pentane, hexane and unsaturated hydrocarbons.

It has been discovered that this liquid fraction composed of butane, pentane, hexane and unsaturated hydrocarbons, upon further subjection to heat and pressure, will form valuable products that are useful in dyeing lubricating oils.

In accordance with this invention, it may be accomplished in the following manner:

A liquid fraction composed of butane, pentane, hexane and unsaturated hydrocarbons of about the same boiling points as butane, pentane and hexane, is separated from the other gases and liquids that are produced by subjecting petroleum oils to cracking temperatures and pressures. A fraction boiling from 10 to 300 F. is found to contain these compounds and is suitable for this process. This liquid fraction, composed mainly of hydrocarbons having from 4 to 6 carbon atoms, is subjected to a heat treatment under pressure to further crack and also to polymerize some of the hydrocarbons. The temperature and pressure to which these hydrocarbons may be subjected are a cracking temperature and a pressure in excess of 100 pounds per square inch. The preferred temperature is above 700 F. and the pressure above 1000 pounds gauge. Higher temperatures and. pressures may be used such as 900 F. and 2030 pounds gauge'pressure. Substantial cracking starts at a temperature of about 785 F. and 1600 pounds gauge pressure. With the raw material described above, the desired operating temperature is about 810 F. at a pressure of about 1920 pounds gauge. The oil is maintained at the cracking temperature and pressure for about one-half hour and allowed to cool slowly, generally over a period of about one and one-half hours. 'The gases and lower boiling point oils are then removed by distillation from the higher boiling point oils that have been formed. In this case, the amount of higher boiling oil formed is about 8 to 9% based on the charge. This is subjected further to vacuum distillation and about 4 to of a highly colored viscous oil, boiling above 286 F. at a high vacuum of 30 inch mercury pressure, that is, at about 10 mm. mercury pressure in the skill, is recovered as bottoms.

This highly colored oil which possibly contains a resin, upon mixing with a lubricating oil, imparts a rich green fluorescence to the oil giving a red color when viewed by transmitted light.

If desired, the liquid fraction may be first fractionated to separate the butane and the, unsaturated hydrocarbons having a boiling point similar to that of butane and this fraction subjected to cracking and polymerization to form the highly colored lubricating oil dye. This fraction has been found to contain about 35% of unsaturated hydrocarbons and therefore is a concentrated raw material for preparing the dye. Other light unsaturated hydrocarbon compounds may be subjected in the same manner. For instance, the light fractions from the pyrolysis of natural gases, or vapor phase cracked gasoline or aromatics may be so treated.

The foregoing, description is merely illustrative and various alternative procedures may be made within the scope of the appended claims in which it is my intention to claim all novelty as broadly as the prior art permits.

I claim:

1. A lubricating oil possessing a green fluorescence, comprising a mixture of a petroleum lubricating oil with a minor proportion of a heavy condensate recovered from the treatment of a normally gaseous hydrocarbon at a temperature above 700 F. and a pressure above 1000#/sq. in.

2. A lubricating oil possessing a green fluorescence, comprising a mixture of a petroleum lubricating oil with a minor proportion of a heavy condensate recovered from the treatment of a normally gaseous unsaturated hydrocarbon at a temperature above 700 F. and a pressure above 1000#/sq. in.

3. A lubricating oil possessing a green fluorescence, comprising a mixture of a petroleum lubricating oil with a minor proportion of a heavy condensate recovered from the treatment of a normally gaseous hydrocarbon at a temperature of about 700 to 900 F. and a pressure of 1000 to 2000#/sq. in.

4. A lubricating oil possessing a green fluorescence, comprising a mixture of a petroleum lubricating oil with a minor proportion of a heavy condensate recovered from the treatment of a hydrocarbon of 4 to 6 carbon atoms per molecule at a temperature above 700 F. and a pressure above 1000#/sq. in.

5. A lubricating oil possessing a green fluorescence, comprising a mixture of a petroleum lubricating oil with a minor proportion of a heavy condensate recovered from the treatment of a distillate fraction of a cracked petroleum oil, said distillate fraction consisting substantially completely of hydrocarbons of 4 to 6 carbon atoms per molecule, at a temperature of about 700 F. to 900 F. and a pressure of 1000 to 2000#/sq. in.

6. A lubricating oil possessing a green fluorescence, comprising a mixture of a petroleum lubricating oil with a minor proportion of a heavy condensate obtained by subjecting a distillate fraction consisting substantially completely of hydrocarbons of 4 to 6 carbon atoms per molecule, said distillate fraction being obtained by cracking a normally liquid petroleum oil, to a temperature of about 700 to 900 F. and a pressure of 1000 to 2000#/sq. in., whereby both cracking and polymerization occur with formation of relatively higher boiling point products, subjecting at least the heavier portions of the resulting products to vacuum distillation and separately recovering the said heavy condensate as a viscous oily residue invol-atile under high vacuum.

EJNAR W. CARLSON. 

